Piezo1-mediated mechano-energetics regulate CAR T cell function.

CAR T cell cytotoxicity requires generating immense mechanical force, but the energetic costs of this process remain poorly defined. While metabolic reprogramming fuels effector function, its mechanistic connection to mechanotransduction remains unclear. By directly measuring the synaptic force and mechanical energy of single CAR T cells and linking them to their metabolic state, we proved that the mechano-energetic efficiency is a fundamental determinant of cytotoxic potency. We discovered that the mechanosensitive ion channel Piezo1 couples cytoskeletal dynamics to metabolic rewiring via Ca(2+)-Wnt-Rac1 signaling. Disrupting Piezo1 cripples glycolytic and mitochondrial ATP production, causing energetic stress and impaired cytotoxicity. Notably, Piezo1 activity follows a Goldilocks principle: intermediate level maximizes activation and cytotoxicity, whereas either hypoactive or hyperactive Piezo1 states impair mechano-metabolic fitness and drive dysfunction in patient and exhausted CAR T cells. Our work establishes mechano-metabolic coupling as a core regulator of CAR T cell fitness and pinpoints Piezo1 tuning as a new strategy to enhance cancer immunotherapy.